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    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
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    <p>Hello</p>

    <script>
        //在p标签同级下面增加一个p标签

        $("p").after("<p>world</p>")   //前面插入


        $("p").before("<p> what can I say</p>")  //后面插入
    </script>

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